FIG. 4.

Subcellular localization and expression of NTD mutants in HeLa cells. (a) Subcellular localization of NLS mutants. Myc-PK localized in the cytoplasm (39); NTD and ΔR58 targeted this protein into the nucleus, while ΔK62 and ΔR65 did not. (b) Immunoblotting analysis of PK-NTD and mutant fusion proteins. PK was truncated by a KpnI site at amino acid 443 during cloning so that PK-NTD is approximately the same size as PK. PK-ΔK62 and PK-ΔR65 had a lower gel mobility than expected, possibly because NTD is modified in the cytoplasm. Phosphatase treatment did not alter the gel mobility of PK-ΔK62 and PK-ΔR65. M.W., molecular weight.